1. Field of the Invention
The present invention relates generally to automated welding, and in particular to a multi-station, gantry-based system for positioning and controlling robotic-arm welders for automatically welding rotatably-mounted workpieces.
2. Description of the Related Art
Automated or “robotic” manufacturing commonly involves computerized operation, control and positioning of tooling, equipment and workpieces. Robotic manufacturing has many advantages, including precision, repeatability, safety, efficiency and cost. Moreover, automated manufacturing facilities can operate continuously with relatively little downtime. Labor can be used efficiently by preprogramming the automated equipment for tasks which might otherwise be done manually. Workers are thus not exposed to dangerous, repetitive tasks and various hazards.
Robotic welders are an example of high-precision, computer-controlled automated manufacturing equipment. They are commonly used on assembly lines for a wide variety of products fabricated from metal. Vehicles and other products can be robotically welded to relatively tight tolerances. Robotic weldments are typically relatively uniform in strength and appearance, thus contributing to high quality finished goods.
Automated production often involves precisely and simultaneously coordinating movements of tooling and workpieces. For example, assembly line production generally involves moving workpieces from station-to-station where different operations are performed. Such assembly line tasks commonly include welding procedures, which can be done manually by welders or automatically by robots. Robotic arms with multiple articulated members can be preprogrammed to accomplish many of the tasks previously done by hand, and often achieve greater uniformity and precision. With precise control, the robotic arms can maneuver inside assemblies through multiple pivotal axes of movement. The computerized control system can precisely monitor and control attitudes and positions in three dimensions. The workpieces themselves can also be manipulated and synchronized with the welding equipment movements. For example, the workpieces can be turned as necessary to enable welding through 360° around joints. Both workpieces and welders can be simultaneously moved through three dimensions for optimal positioning and access. Relatively complex weldments can thus be achieved by preprogramming the equipment.
Movable gantries are commonly used in manufacturing for positioning manufacturing equipment relative to workpieces. For example, a computer control system can be preprogrammed to precisely place a gantry and the tooling mounted thereon over a workstation containing a workpiece. Upon completing a preprogrammed task, the gantry can automatically relocate to another workstation and workpiece. Alternatively, factory production workstations can include equipment for repositioning the workpieces. For example, workpieces can be rotatably mounted in workstations for access by tooling, including welding and painting equipment.
Gantry-based systems can be configured with elevated tooling and equipment. Such an arrangement has the advantage of locating tooling and equipment overhead, thus leaving factory floors free for workstation placement. Mobile gantries and equipment normally require power and utility lines which are configured for accommodating movements.
The multi-station, gantry-based welding system of the present invention facilitates performing multiple manufacturing operations precisely and simultaneously. Multiple workstations can be serviced by a single gantry configured for movement from station-to-station. The system of the present invention is configured for overhead placement of the power and utility lines, thus leaving the factory floor space below open for other uses. Locating the power and utility lines overhead tends to increase safety because they are less likely to be engaged by workers and equipment moving about the factory floor. Moreover, greater gantry mobility can be achieved by running the power and utility lines overhead because the elevated areas in factories tend to be more open than the factory floors. Space on factory floors is often at a premium with personnel, materials, equipment, forklifts, etc. in motion at floor levels.
The workstations movably mount respective workpieces, which are synchronized with gantry movements and also with robotic welding arms movably mounted on the gantries. Such simultaneous workpiece, gantry and equipment movements can be coordinated to consistently produce finished products, which can include complex shapes and component assemblies. By synchronizing the workpiece, gantry and equipment movements, such procedures can be accomplished from virtually unlimited relative orientations and positions of the moving parts of the system. A wide variety of finished products can be produced using a variety of procedures.
Heretofore there has not been available a multi-station, gantry-mounted welding system with the advantages and features of the present invention. In addition to robotic arm welding systems, other tooling and equipment can likewise be movably mounted on a gantry for movement relative to the workstations wherein the movable workpieces are located.